ChromaCheck

About

ChromaCheck shows you what your website looks like to the 300 million
people worldwide with color vision deficiency — and tells you exactly
where your design is failing them.

━━━ SIMULATE REAL VISION ━━━

Apply scientifically calibrated filters to any webpage to see it through
seven types of color blindness:

  • Green weak (Deuteranomaly) — the most common form, ~5% of men
  • Red weak (Protanomaly)
  • Green blind (Deuteranopia)
  • Red blind (Protanopia)
  • Blue weak (Tritanomaly)
  • Blue blind (Tritanopia)
  • No color vision (Achromatopsia)

Plus a high-contrast assistive view for low-vision users.

The simulation uses the Brettel-Viénot-Mollon (1997) and Machado et al.
(2009) color projection models — the same math used in vision research.
Not a tinted overlay, not a guess. The real perceptual transform.

━━━ AUDIT WHAT MATTERS ━━━

One click runs a full WCAG 2.1 contrast audit on every text element on
the page:

  • AAA, AA, and A compliance counts
  • Overall compliance percentage
  • Specific failing elements with selectors, ratios, and text snippets
  • Click any failure to scroll directly to it on the page

━━━ CATCH WHAT OTHER TOOLS MISS ━━━

ChromaCheck's killer feature: it re-runs the contrast audit through each
color blindness projection and flags regressions — pairs that pass for
normal vision but fail under deuteranopia, protanopia, or tritanopia.

This is where most accessibility issues actually live. A red-on-green
"required field" indicator that looks fine to you might be invisible to
the colorblind reviewer on your team. ChromaCheck finds those before
they ship.

━━━ FAST AND PRIVATE ━━━

  • Audits run locally in your browser. No data leaves your machine.
  • No accounts, no telemetry, no network requests.
  • No host permissions — only touches a tab when you click the icon.
  • Open source. 

━━━ WHO IT'S FOR ━━━

  • Designers and developers shipping accessible interfaces
  • Accessibility specialists auditing sites
  • Product managers reviewing what users with CVD actually experience
  • Anyone curious how their friend, parent, or colleague sees the web

About 1 in 12 men and 1 in 200 women have some form of color vision
deficiency. They're using your site right now. ChromaCheck helps you
make sure they can.